317 JASEM ISSN 1119-8362 All rights reserved J. Appl. Sci. Environ. Manage. June, 2011 Vol. 15 (2) 317 - 325 Full-text Available Online at www.bioline.org.br/ja Fracture analysis of concrete gravity dam under earthquake induced loads 1 ABBAS MANSOURI; 2 MIR AHMAD LASHTEH NESHAEI; 3 REZA AGHAJANY 1 Civil Engineering, Islamic Azad University (South Branch of Tehran)Tehran, Iran 2 Civil Engineering, University of Guilan, Rasht, Iran 3 Civil Engineering, Islamic Azad University, (North Branch of Tehran), Tehran, Iran E-mail: [email protected] Tel: +98.9111281372 ABSTRACT: In this paper, seismic fracture behavior of the concrete gravity dam using finite element (2D) theory has been studied. Bazant model which is non-linear fracture mechanics criteria as a measure of growth and smeared crack was chosen to develop profiles of the crack. Behavior of stress - strain curves of concrete as a simplified two-line, dam and reservoir system using the formulation of the Euler - Lagrange was chosen. According to the above models, Koyna concrete gravity dam were investigated by the 1967 earthquake record. The results provide profiles of growth and expansion first with the effects of reservoir and second without it. Comparison of the obtained results shows good agreement with the works of the other researchers. @ JASEM Keywords: Seismic fracture; Smeared crack; Non-linear fracture mechanics; Concrete gravity dam. The seismic behavior of concrete dams has been the subject of extensive research during the past decade concerning dam safety during earthquakes. Chopra et al (1972), studies seismic behavior of dam’s crack path by using linear elastic analysis. The analysis shows, places that are in damage or and risk of the concerning stability of structure. Pal (1976) was the first researcher who examined Koyna dam by using non-linear analysis. In this research, assuming no effect of reservoir, being rigid foundation, smeared crack model use for crack expansion and strength criteria to crack growth, Koyna dam was analyzed and was shown that the results of material properties and element size are very sensitive. Figure 1(a) crack zone in the dam of which resulting from this analysis are shown. Skrikerud (1986) studied concrete dams through a case study on Koyna dam and by employing discrete crack for crack growth and strength criteria for crack expansion. In their study the growth of crack at each step of growth, the length of the crack tip element was considered that this is the final results were effective. He interpreted the results of their model, due to expansion mismatch with the cracking in their analysis of real crack in the dam, no match Foundation and reservoir interaction and lack of real values of characteristic parameters dam announced. Crack profiles from the analysis left in Figure 1(b) are presented. El-Aidi and Hall (1989) did a research on seismic fracture of Pine flat dam. Smeared crack model and strength criteria for crack expansion and growth were used. In their analysis is considering the reservoir – dam and foundation – dam interaction was crack profile presented. Figure 1(c), cracking in the dam will provide analysis. Fenves and Vargas-Loli also studied Pine flat dam by using fracture mechanics criteria for crack growth and smeared crack model to crack expand (Uang and Bertero, 1990). They apply different coefficients of Taft earthquake record, regardless of the effect by foundation; Pine Flat dam in two cases with and without the effect of the reservoir was analyzed. In this study the effect of hydrodynamic pressure on the seismic behavior in the dam with the crack profiles presented. The results of this analysis were shown in Figure 1(d). Bhattacharjee and Leger (1994) presented detailed results of their study on nonlinear analysis models of gravity concrete dams. Nonlinear Behavior in Seismic their smeared crack models were used. In their analysis, dynamic and static results of this model have been compared to laboratory results and cracks formed in Koyna gravity dam and approved. Results from this analysis in Figure 1(f) can be seen. Ghaemian and Ghobarah (1999) to assess the seismic behavior of concrete dams in the two-dimensional space of the smeared crack model presented in 1993 and 1994 by leger and Bhattacharjee used. 2D seismic fracture behavior of the Koyna dam were examined by Ganglia et al, (2000).In their studies smeared crack model for crack growth and non-linear fracture mechanics criteria for the expansion of cracks were used. Lohrasbi and Attarnejad (2008) also used fracture mechanics theory in their analysis, to evaluate the smeared crack model and discrete crack model. Nonlinear seismic behavior of the Koyna dam by considering Dam and Reservoir interaction examined by Mirzabozorg and Ghaemian (2005). They analysis Koyna dam under dynamic loading, defined fracture mechanics of the fracture region and the smeared crack model. Through an article published in 2005, Calayir and Karaton (2005) evaluated the response of seismic fracture in gravity concrete dams. In their own study with regard to dam and reservoir interaction, Koyna dam to the finite element method with Lagrange - Lagrange formulation, analysis and the crack profiles growth were presented. Results from this analysis in Figure 1(e) can be seen. Cai et al
Fracture analysis of concrete gravity dam under earthquake induced loads
May 23, 2023
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